Linux多播后續套接字竊取數據

Question

我正在嘗試使用Boost ASIO UDP套接字來多播數據。 我相信我的發送者和接收者都可以正常工作，因為單個發送者和接收者都可以正常工作。 但是，當我們現在在同一台計算機上有多個接收器時，只有最后綁定到該地址的接收器才可以接收數據。 我相信這可能是配置問題，但是我將盡一切可能。

網絡：

[root@dev ~]# ifconfig
eth1      Link encap:Ethernet  HWaddr 00:0C:29:C1:34:B7  
          inet addr:192.168.6.131  Bcast:192.168.6.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fec1:34b7/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:25060380 errors:0 dropped:0 overruns:0 frame:0
          TX packets:24562809 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2030905679 (1.8 GiB)  TX bytes:5249474660 (4.8 GiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:2687213321 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2687213321 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1633558802477 (1.4 TiB)  TX bytes:1633558802477 (1.4 TiB)

組播發送方：

MulticastSender(const std::string& listenaddress,
                const std::string& multicastaddress,
                const unsigned short port) : Address(boost::asio::ip::address::from_string(listenaddress)),
                                             Port(port),
                                             Endpoint(Address, port),
                                             Socket(IOService, Endpoint.protocol()),
                                             Work(IOService) {
        Socket.set_option(boost::asio::ip::multicast::join_group(boost::asio::ip::address::from_string(multicastaddress).to_v4(), boost::asio::ip::address::from_string(listenaddress).to_v4()));
        auto self = this;
        WorkThread = std::thread([self]()
                                 {
                                     self->IOService.run();
                                 });

    }

組播接收器：

MulticastReceiver(const std::string &listenaddress,
                  const std::string &multicastaddress,
                  const unsigned short port) : Socket(IOService),
                                               ListenAddress(listenaddress),
                                               MulticastAddress(multicastaddress),
                                               Work(IOService) {
    boost::asio::ip::udp::endpoint listenendpoint(boost::asio::ip::udp::v4(), port);
    boost::system::error_code ec;
    Socket.open(listenendpoint.protocol(), ec);
    Socket.set_option(boost::asio::ip::udp::socket::reuse_address(true), ec);
    Socket.set_option(boost::asio::ip::multicast::enable_loopback(true), ec);
    Socket.bind(listenendpoint, ec);
    Socket.set_option(boost::asio::ip::multicast::join_group(boost::asio::ip::address::from_string(multicastaddress).to_v4(), boost::asio::ip::address::from_string(listenaddress).to_v4()), ec);
    auto self = this;
    WorkThread = std::thread([self]()
                             {
                                 self->IOService.run();
                             });
    Socket.async_receive_from(boost::asio::buffer(Buffers[BufferIndex], MaxLength), Endpoint,
                              boost::bind(&MulticastReceiver::HandleReceiveFrom, this,
                                          boost::asio::placeholders::error,
                                          boost::asio::placeholders::bytes_transferred));
}

對於listenaddress我嘗試了使用192.168.6.131指定接口，還嘗試了使用0.0.0.0將其留給系統。 我還嘗試了join_group兩種變體， join_group在其中指定接口或不指定接口。

當我運行應用程序時，運行netstat -gn時，可以在正確的地址中看到正確的成員數。

這是我對發送者和接收者的輸入：

listenaddress = "0.0.0.0"; // or listenaddress = "192.168.6.131"; // eth1
multicastaddress = "239.140.127.0";
port = 35000;

我正在CentOS 6.6 with kernel Linux dev 2.6.32-504.el6.x86_64運行此程序，並運行Boost 1.55.0 。

Answer 1

我無法弄清楚為什么多播不能在該設置上工作，但是我能夠使代碼在其他地方工作，所以我想我也可以將更改發送給發送方和接收方。

組播發送方：

MulticastSender(const std::string& multicastaddress,
                const unsigned short port) : Port(port),
                                             Endpoint(boost::asio::ip::address::from_string(multicastaddress), port),
                                             Socket(IOService, Endpoint.protocol()),
                                             Work(IOService) {
    auto self = this;
    WorkThread = std::thread([self]()
                             {
                                 self->IOService.run();
                             });

    std::string data = "Test message";
    Socket.async_send_to(boost::asio::buffer(data), Endpoint, boost::bind(&MulticastSender::SendHandler, this, boost::asio::placeholders::error));
}

組播接收器：

MulticastReceiver(const std::string &listenaddress,
                  const std::string &multicastaddress,
                  const unsigned short port,
                  const int numbuffers) : Socket(IOService),
                                          ListenAddress(listenaddress),
                                          MulticastAddress(multicastaddress),
                                          Work(IOService) {
    boost::asio::ip::udp::endpoint listenendpoint(boost::asio::ip::address::from_string(listenaddress), port);
    boost::system::error_code ec;
    Socket.open(listenendpoint.protocol(), ec);
    Socket.set_option(boost::asio::ip::udp::socket::reuse_address(true), ec);
    Socket.set_option(boost::asio::ip::multicast::enable_loopback(true), ec);
    Socket.bind(listenendpoint, ec);
    Socket.set_option(boost::asio::ip::multicast::join_group(boost::asio::ip::address::from_string(multicastaddress)), ec);
    auto self = this;
    WorkThread = std::thread([self]()
                             {
                                 self->IOService.run();
                             });
    Socket.async_receive_from(boost::asio::buffer(Buffers[BufferIndex], MaxLength), Endpoint,
                              boost::bind(&MulticastReceiver::HandleReceiveFrom, this,
                                          boost::asio::placeholders::error,
                                          boost::asio::placeholders::bytes_transferred));
}